Network.MQTT

An MQTT client library.

Setup

run :: Config -> IO Terminated

Connect to the configured broker, write received Publish messages to the cPublished channel and handle commands from the cCommands channel.

Exceptions are propagated.

data Terminated

Reasons for why the connection was terminated.

Constructors

ParseFailed [String] String

at the context in [String] with the given message.

ConnectFailed ConnectError

UserRequested

disconnect was called

Instances

Show Terminated

disconnect :: Config -> IO ()

Close the connection after sending a Disconnect message.

See also: Will

data Config

The various options when establishing a connection. See below for available accessors.

defaultConfig :: Commands -> TChan (Message PUBLISH) -> Config

Defaults for Config, connects to a server running on localhost.

data Commands

The communication channel used by publish, subscribe, etc.

mkCommands :: IO Commands

Create a new Commands channel.

There should be one channel per MQTT connection. It might be reused by subsequent connections, but never by multiple connections concurrently.

Config accessors

cHost :: Config -> HostName

Hostname of the broker.

cPort :: Config -> PortNumber

Port of the broker.

cClean :: Config -> Bool

Should the server forget subscriptions and other state on disconnects?

cWill :: Config -> Maybe Will

Optional Will message.

cUsername :: Config -> Maybe Text

Optional username used for authentication.

cPassword :: Config -> Maybe Text

Optional password used for authentication.

cKeepAlive :: Config -> Maybe Word16

Time (in seconds) after which a PingReq is sent to the broker if no regular message was sent. Nothing means no limit.

cClientID :: Config -> Text

Client ID used by the server to identify clients.

cLogDebug :: Config -> String -> IO ()

Function for debug-level logging.

cPublished :: Config -> TChan (Message PUBLISH)

The channel received Publish messages are written to.

cCommands :: Config -> Commands

The channel used by publish, subscribe, etc.

cInputBufferSize :: Config -> Int

Maximum number of bytes read from the network at once.

Subscribing and publishing

subscribe :: Config -> [(Topic, QoS)] -> IO [QoS]

Subscribe to the Topics with the corresponding QoS. Returns the QoS that were granted (lower or equal to the ones requested) in the same order.

The Topics may contain wildcards.

unsubscribe :: Config -> [Topic] -> IO ()

Unsubscribe from the given Topics.

publish :: Config -> QoS -> Bool -> Topic -> ByteString -> IO ()

Publish a message to the given Topic at the requested QoS level. The payload can be any sequence of bytes, including none at all. True means the server should retain the message for future subscribers to the topic.

The Topic must not contain wildcards.

Reexports

module Network.MQTT.Types